The Devil You Don't Know
by Evalon Knights
Summary: When she almost dies in a fire that destroyed her family, and a priceless relic is stolen, Nicole Tryst makes one final gamble. Too bad the book wasn't exactly accurate about what would happen, and just why are there two handsome - if injury prone - men following her? Rated T to be safe Sorry about nonexistent line breaks in Chapter 3. -.-
1. A Demon and A Contract

A/N: Hey guys, long time no see. I know, it's been years since I last wrote anything for you. I'm sorry. I'm gonna shoot for updating at least once a week, that way you guys aren't left waiting forever for an update. As always, reviews are welcome, flames ignored. Enjoy my latest creation. ;-)

Disclaimer: I do not own Black Butler, or Supernatural. I know, it kills me too. T_T

Prologue

Everything was suddenly calm. She wasn't exactly sure why. The last thing she remembered before blacking out was reading a spell in an old book while her body was being burned in her house. Maybe she was dead. Looking around it seemed like the most logical conclusion, unless she was comatose and dreaming this whole thing. Her surroundings were grey with black feathers falling from the sky, and off to her left, maybe twenty feet away, was a raven perched on a dead yew tree.

"Am I dead?"

"That depends."

She jumped. Of all the voices she'd have expected from a raven - had she ever expected a raven to talk - it certainly wasn't a soft, deep voice. The raven eyed her amusedly, and she was distinctly aware of an undercurrent of terror. Whatever that bird was, it certainly wasn't wholesome.

"You talk."

It snorted, "Of course I speak. How rude."

Nikki frowned at it. "Why am I here?"

"You tell me. You're the one who summoned me. To do so successfully means you must want something rather desperately."

She turned her head away, staring up at what should have been a burning roof. What did she want? Clearly that weird spell had worked, and if she survived she resolved to do some research on it, but what contract? She could hear the bird chuckling as she thought about it.

"Who are you?"

It cocked its head to the side. "Didn't you read the passage before the spell? I can give you whatever you want. For a price, of course."

Everything clicked into place, then. She _had_ read the passage, albeit rather hurriedly. Her family had been murdered, burned alive in their home after a precious relic was stolen from her father's study. She'd been asleep when the heat got to her, prompting her to go find her parents and escape, but the thief had been thorough. Whoever it was had ensured that anyone on the second floor would be trapped, and doomed to die. It was when she'd found her parents in the library that she'd found the book, and while the fire tore at her skin, she'd read the spell. Now she remembered why she'd attempted this gambit.

"My family was murdered. I want to find out who, why they did it, and I want to destroy them."

The raven tutted. "Revenge is so cliché. Surely there is more to your wish?"

Nikki turned her brown eyes to the raven, her frown deepening. She didn't want to overplay her hand. The relic that was stolen was not only priceless, but, according to her father, it was incredibly dangerous. He wouldn't tell her everything, but she remembered that he said it would be catastrophic if it fell into the wrong hands.

"Oh dear, you don't trust me. Well, that's actually smart of you. However, if you intend to make a contract with me, Nicole Tryst, you've got to give me a better reason than revenge."

Her eyes narrowed. "A key. The killer, or killers, stole some kind of key from my father's study. I've got to get it back and destroy it."

The bird was regarding her closely, as if weighing the risk verses the reward. If the book were correct, the reward would be her soul. Every moment seemed like eternity, and Nikki was getting antsy. The longer they waited, the further the killer got, and the colder the trail went.

"I'll do…I'll _give_ anything. I've got to get this key back. My father said it could be bad in the wrong hands."

"Bad?"

"End of the world bad, which would mean no more contracts, and no more souls."

"Well, that would be depressing. I'd go hungry, now wouldn't I?" The raven, which she now recognized as the demon from the book, sighed. "Very well. I will help you get revenge and retrieve this key. All we need to do is finalize the price of the contract."

This was the part that Nikki dreaded. Her father wasn't kidding when he'd said she was agonizingly bad at negotiating. Her inability to do so often resulted in longer than necessary punishments, purely because she couldn't control her mouth. Now she was negotiating something far more dire, and with higher stakes.

"I do remember you saying you'd give anything to get this key, yes?"

"I did…but I thought you wanted my soul?"

The demon laughed. "Well, that's the usual price, yes. However, I've been bored lately, and there's something I've been wanting to try."

Her father was right. Her mouth got her in monumental trouble, and this was the crowning instance. She was negotiating the possible end of the world with a demon, and she said she'd give anything to prevent it. It was true, but throwing all of one's cards on the table was never a wise thing to do. Now she was stuck.

Nikki took a deep breath, having a sinking feeling that she knew what he would say. "What do you want, then, if not my soul?"

Without answering, the raven took off, and the scenery changed. Suddenly, it was pitch black, and the only thing she could see were two crimson eyes staring at her hungrily. Despite the tremors running along her body, Nikki lifted her chin defiantly, her eyes locked with his. In another second, the eyes were gone, and an arm had slipped around her waist and pulled her back.

"Simple," he purred. "I want you."

"What? What do you mean?"

His voice was dark against her skin. "In exchange for my service, Nicole, you will give yourself to me. For eternity."

Well this took a drastic turn.

"You want me? As a slave?"

"More of a pet, of sorts. It's up to you, Nicole. Either you accept the terms of the contract and prevent the end of the world, or you walk away, and presumably wake up on life support in a hospital. Regardless of what happens, I still get something interesting. I either get you, or I get to watch the world burn. You might want to make your choice quickly. I'm not well known for patience."

So that was it. If she didn't agree to the terms of the contract, then the world could very well end up like a rotisserie chicken. Slightly off topic, she realized that she had to be hungry to liken the end of the world to something being slow roasted, and shook her head. There really was no choice that she could see. It was either save the world and avenge her parents, or die as the world falls apart. Fuck.

"I don't have much of a choice, do I? Fine. Let's make the contract."

The demon spun her around and pulled her close, his eyes boring down into her. She got the vague sense that he was smirking down at her, and it was all she could do to not step on his foot out of sheer irritation. Long nails lightly scraped against her cheek as he lifted her chin, forcing her to keep looking him in the eyes.

"You are a bold one…this will most definitely be fun," he chuckled, his breath warm on her face. "Before we finalize the deal, I do have to warn you - part of the job. If you do this, the Gates to Heaven will forever be closed to you."

Nikki scoffed. "That's fairly obvious since I'm agreeing to being with you for eternity."

"Sassy. That mouth could get you into trouble, Nicole."

"Probably not the last time I'll hear that…it's certainly not the first."

He laughed again, his lips dangerously close to hers. Of all the possible futures she could have seen her self having, being a demon's pet was not one of them.

"One last thing…"

She arched an eyebrow. "Just one?"

He growled slightly. "Where shall we put the contract mark? The more visible it is, the more powerful it is."

"Um…"

"How do you feel about eye patches?"

"Eye patches? Why? We aren't being pirates."

The eyes narrowed at her, and she had to admit that this was really the mouthiest she'd ever been. Part of her wondered if it might not be a defense mechanism.

"I could put it on your right eye. It would look rather lovely there, I think."

"On my eye? Could you put it on the left? My right eye is my dominant eye."

He rolled his eyes. "I could, but that would make you a tad less reliant on me, and where's the fun in that."

She just blinked. "Yeah…put it on the left eye."

"Is that an order?"

"I order you to put the contract mark on my left eye."

Before she could register what happened, he bent down and kissed her. His lips were soft and warm, which was something else she hadn't expected. They should have been cold and cruel, and they certainly shouldn't have been so sensual. As the kiss continued, he put his hand on her eye, and a sudden white hot pain exploded in her head. A scream tore from her throat, and the crimson eyes watched her with sadistic pleasure as she collapsed in his arms.


	2. And Then There Were None

Disclaimer: Nothing's changed. I still don't own Kuroshitsuji or Supernatural. *Sniffle*

Chapter One

Nikki groaned as she sat up, a headache pounding right behind her right eye. What exactly had happened last night? As she sat in the rather comfortable hotel bed trying to remember what happened, a very thin man in his mid twenties leaned against the doorframe. She looked up at him for a moment, and frowned.

"Who the hell are you?"

He chuckled. "Oh my. You don't remember, do you?"

She groaned and flopped back on the bed. That voice brought back everything. The fire, the key…the contract. Her eyes closed, and she flipped the blankets over her head. It had to be a very bad dream. She couldn't have possibly agreed to be a demon's eternal pet…right?

"Oh, you did, my dear. Although, right now I am simply your assistant."

"Is that all?" She responded faintly. "I died in a fire, and came out with a demon for an assistant."

He arched an eyebrow. "For now. Once the contract is complete, I do believe roles become somewhat reversed."

"I thought you said I wasn't going to be a slave."

"I did, and you won't be. I have no use for a slave, but the pets in Hell are…"

Nikki blinked. "You have pets in Hell?"

"Yes, but they're not like the things you're used to. I'd rather have a cat."

Nikki stared at him for a moment before giggling. Her demon assistant was a cat person. All things considered, it was kind of funny.

"I do believe we have work to do, Miss. Tryst."

"Mistress? I could get used to that." she said, still giggling as she got up. "Any chance you found anything out while I was sleeping off my hangover?"

He gave her a sidelong look. "That isn't what I said, and you know it. That also wasn't a headache. That was just a side affect of me placing the contract mark on your left eye. And, finally, yes. Since we're looking for a key to a gate to Hell, it stands to reason that we should look wherever there are supernatural happenings. Ten people have died in five days in a small town in North Dakota."

Nikki looked at her left eye in the mirror. Sebastian hadn't been kidding about the eye patch. If she went out with her eye looking like this she'd draw far too much attention. Then again, a girl walking around with an eye patch was bound to draw substantial attention, anyway.

"You got an eye patch, right? Walking around with this on my eye is probably going to cause problems."

Sebastian handed her a black leather eye patch. "Naturally, although I think you look better without it."

"Suck up," she snorted. "What did you find, again?"

The demon butler smiled, and swiveled the computer he was using so she could see it. "Ten Deaths in a five day period, two separate causes of death."

"This is going to be difficult to get used to. How did they die, again?"

"Well, five died from having their hearts ripped out. The other five committed suicide."

Nikki stared at the computer screen, willing her right eye to adjust to working on its own. Sebastian was watching her closely as she sat down and studied the articles he'd pulled up for her. If he expected her to be squeamish, he was right, but she wasn't going to let him see that. Hearts torn from their bodies? She'd never heard of anything like that except in horror stories, and historical accounts of human sacrifice. That just left the suicides. As she kept reading, Sebastian disappeared into the kitchenette, and scoffed at the "sad excuse for tea" that was stocked.

Suddenly, she stood up, gathered some things, and turned to Sebastian, who looked about ready to throw the tea out a window. Not that she'd complain, she'd never liked hot tea, but she was fairly certain that the hotel owners wouldn't appreciate a broken window as a review of their tea selection. It was almost adorable, really.

"Come on, Sebby. Let's go see what's going on in North Dakota…and please don't throw the tea out the window. People actually drink that."

He wrinkled his nose. "I can't imagine why. It's not as if it's that difficult to brew tea the right way."

"American's aren't as big on tea as the British," Nikki shrugged. "We drink coffee. Anyway, let's get a move on. If this case will lead to the key, then we should go before the trail goes cold."

Sam sighed irritably as Dean snored in the seat next to him. Admittedly, it had been relatively calm, all things considered, but seriously. The man sounded like a cheese grater on a cinderblock. Slowly, a small smirk began to play on the younger man's lips. It had been a while since he'd done this, after all, and everyone needed some fun once in a while. So, while his dear brother slept soundly in the passenger's side, Sam put a little ipecac syrup in his soda.

"Hey. Dean!" Sam nudged him awake. "Wake up. We're here."

Sam handed him the soda and watched as his brother took a large gulp, and looked up at the house surrounded by cop cars. True, the ipecac syrup would take a bit to take effect, but sometimes the best pranks were the ones that hit later. Especially if he was initiating a prank war, and let's be honest, that's exactly what he did.

"I guess we should see what's going on. Maybe it has something to do with the other ten deaths."

Dean shook his head. "Somebody loses a heart and the other bastards off themselves. Witches or demons?"

Sam shrugged. "Could be werewolves who can't come to terms with what they did."

"How often do we get that lucky?"

"Not often."

"Right. Let's put on the fed threads and see what's going on."

The two brothers slipped into a restroom and put on their suits, now looking like federal agents in cheap suits. As they were walking up to the house, they saw a young woman with an eye patch, and an inexplicably creepy young man talking to a relative of the victim. The woman was writing in a notepad, while the man idly looked about the exterior of the house, a look of distaste on his face. When she saw his face, she gave the family member of the victim a sympathetic look, and surreptitiously stepped on the man's foot.

"That is one creepy ass dude."

"We've seen a lot of creepy guys over the years, Dean."

Dean frowned. "Yeah…but there's something really…off about him."

"I know what you mean."

Putting their misgivings aside for the moment, the two brothers stepped up to where the three were talking. The girl turned to them, affecting a smile, while the guy watched passively from the side. Even up close the guy gave Dean a bad feeling, especially the smile. It looked genuine, but Dean couldn't help but feel like there was some kind of malice behind it.

"Sorry to take up your time, ma'am. It sounds like you've had a rough day. I'll be in touch if I can think of any questions." She turned to the two brothers. "I'll get out of your way now, Mulder, Scully. Have a good day."

With a click of her pen, she sauntered away, the man following her. Dean watched her walk away, his eyebrow arched, and a smile on his face, while Sam shook his head. They really had to get this done before the ipecac took effect. The last thing Sam wanted was Dean retching in the victim's toilet.

"Miss Daweson? I'm Agent Elliott, and this is Agent Savage. We're here to ask you about your son's death."

Elvira Daweson whimpered. "Oh, right. Come on in."

"If you don't mind me asking," Dean started. "Who were those two that you were talking to earlier?"

"Hm? Oh. That was Erin McNab and Ian Holmes. They're reporters."

"Uh huh. Well, Miss Daweson, I don't suggest speaking with the press for a while. They're really quite nosy."

"Oh, um…of course. Would you like some lemonade?"

Sam shook his head. "No, thank you. Can you tell us exactly how you found him?"

Tears welled up in Elvira's eyes. "He…he was in his room. All I did was go out to the movies, and then I stopped at the store. Ronnie and Aaron were always good friends. I…I just don't understand why…."

"I know it's hard, Miss Daweson, but I need you to tell me how you found him."

While Sam questioned Elvira, Dean walked up the stairs to the victim's bedroom, his eyebrows shooting up to his hairline when he saw the massive pool of blood on the floor, and the splatters on the wall and ceiling. Whatever happened, it was certainly messy.

"I found him on his back. He…he looked shocked and terrified…and…and a hole in his chest where his heart should have been." Elvira let out a sob. "And poor Aaron! He was in my kitchen with his head almost off, and my butcher's knife in his hand!"

Sam handed her a tissue. "Did either Aaron or Ron exhibit any unusual behavior before the incident?"

"Not that I can think of."

"I need you to think. Anything. Even something small."

"Well…Aaron said he was going to some club over on Pine Street."

"Thank you, Miss Daweson. We'll keep in touch."

The two men walked to the car, and got in, both frowning. When Sam looked at Dean, he had to fight to keep the smirk from his face. Dean was starting to turn green, and looked a tad bit sick.

"What do you think?"

"I think we should question the other families. Look for a connection." Dean burped, and groaned.

Sam bit the inside of his cheek. "You okay?"

"I don't know. I think I might've eaten something funky." he paled. "Drive, Sammy."

"Sorry?"

"Either get me to the nearest john, or pull over!"

Sam smirked as he peeled away from the Daweson house with Dean groaning next to him. Sometimes simple was best.

Nikki looked down at the body of Ron Daweson, grimacing under the surgeon's mask. The boy's body was stained red, and it looked like someone had just punched a hole in his chest and pulled out his heart with their bare hands. Next to her, Sebastian was looking into the hole, totally unaffected, which wasn't surprising, but was very off-putting. With a gloved hand, he poked and prodded at the hole.

"So…you're telling me that Aaron stuck his hand in Ron's chest and pulled out his heart? What is this? Indiana Jones and the Temple of Doom?"

Sebastian chuckled darkly. "While that was an interesting film, no. This doesn't seem to have any connection to it."

"Sarcasm, Sebby. I was being sarcastic." Nikki sighed. "Anyway, how could a fifteen year old boy break another boy's ribs, and yank out his heart while leaving that kind of a hole?"

He gave her a look. "Must you call me that? I don't have fond memories of that name."

"Well what else am I going to call you? Sebastian is both long and pretentious."

"Good think I happen to be pretentious, then, no?"

She snorted. "Creepy yes. Pretentious? No."

Sebastian gave her a very creepy smile that just screamed "Die. Die a thousand times", and turned back to the body.

Nikki returned to the coroner's report, a frown on her face. Part of her almost wanted it to be the result of a steroid induced rage, but the other part told her that it was something darker than drugs. As she scanned the page, she came across something odd.

"Hey, Sebastian. Says here they found a crystal in his room. One in Aaron's as well."

He cocked his head to the side. "Hm. That is interesting."

"It most certainly is. I'm Agent Elliott, we met briefly at the Daweson place."

Nikki turned to see a man standing in the doorway. He was freakishly tall, muscular, and actually rather handsome, now that she got a good look at him. Smiling, she held out her hand.

"Erin McNab, and that is my associate, Ian Holmes. We're with the paper."

Agent Elliott smiled and shook her hand. "Pleasure to meet you. Did you say the report referenced a crystal? Does it say what kind?"

"Yeah, but I'm not sure why it's relevant. The kids could have been geology nuts."

Sebastian was watching her closely, and she was watching Agent Elliott. He had walked up to the body, and was looking down at the hole, frowning. Whatever he saw, he didn't like, not that Nikki could blame him. Seeing anyone with a gaping hole in their body and a missing organ was kind of unpleasant.

There was something about him that felt off. One thing was sure, he was no federal agent. She'd seen several growing up, even dated one, and none of them wore cheap suits found in a thrift shop. Somebody else was nosing in on her case, and it bothered her.

"Well, it was nice meeting you Scully. Ian and I have to go. We haven't eaten all day, and I can hear his stomach from here." She handed him a card with her current number on it. "Give me a call if you find anything."

"I'll be sure to give you the exclusive, Miss McNab."

The agent returned to the body, and she and Ian left the morgue. Nikki let out a sigh as the sun hit her face, warming it. First the murder/suicides, then the crystal, now mysterious agents who aren't actually agents. What on earth had she gotten into?

"At least I don't have to worry about them arresting me."


	3. Strange Reports

Chapter 2

Sam frowned as he watched Erin and Ian walk away from the morgue. It was highly unusual for a reporter to see the bodies of victims, much less be allowed to poke at them, and the coroner's assistant seemed terrified of Ian. Sam couldn't exactly blame her, the guy had a creepy smile.

Filing that away for later, Sam walked to a local dive and got some food. He really couldn't understand how Dean could eat so much grease and not have to run to the bathroom every five minutes. It was almost inhuman, and very unhealthy. The entire way back to the motel, Sam tried to ignore the grease dripping from the bag, and figure out what was going on.

"We got a problem," Sam said as he opened the motel room door.

"Yeah we do." Dean glared. "Ipecac syrup, Sammy? Really?! I was puking my guts out for the last hour!"

Sam fought back a smirk. "No clue what you're talking about, Dean. When would I have time to do that?"

"You're going to pay for this."

"Sure, Dean. Anyway, I ran into our reporter friends from the Daweson place."

Dean sniffed the food suspiciously before he started eating, and Sam rolled his eyes. As if he'd pull that stunt again. While Dean tore through a double cheese burger, Sam sat down to see what he could find on Erin McNab...until he saw one of his brother's favorite websites pulled up.

"Dean, why is there a porn site on my computer?"

"Mine is updating."

Sam glared, his nostrils flaring. "There's a virus on here!"

"You can fix it, so stop whining." Dean said, his mouth full. "What about that chick with the eye patch?"

"She and her creepy friend were poking at the bodies of the victims." Sam said irritably, now trying to dislodge and remove the Trojan horse virus.

"I didn't think reporters were allowed to do that."

"They're not...YOU DOWNLOADED A PORN APP?!"

Dean sniggered. "Not on purpose. So how'd they get in?"

"I'm going to kill you. No clue, but the assistant seemed scared of Ian."

Dean leaned back as Sam tapped furiously at the computer. Something wasn't adding up with any of this, and it bugged him.

"Guess we have another thing to look into. I don't think their names are Erin and Ian."

Sam ignored him for a moment, his eyes narrowing. "That's because they aren't. There is no Erin McNab or Ian Holmes at the local paper. They don't exist."

Dean arched an eyebrow. "Really? Then who are we dealing with?"

"No idea, but we shouldn't let on that we know they're lying. Maybe they're hunters."

"If they were, wouldn't they have recognized us?"

"Maybe they're new."

"Maybe, but knowing our luck? Let's make sure."

"Guess it's time to go visit Erin McNab and Ian Holmes."

* * *

Nikki tossed her things onto the couch, flopped down, and sighed. The case was starting to look like it had nothing to do with her key, or her parents' deaths, and she was sure the trail was going cold. Sure, she wasn't exactly in a hurry to honor her part of the contract, but she did want to avert a possible resettlement of the entire population of Hell.

Standing back up, she dug in the kitchenette for whiskey. "Did you _have_ to scare the assistant like that?"

"Well how else would you suggest we get in?" Sebastian chuckled.

"We could have been more creative than terrifying the girl."

Nikki turned to face him, and almost had a heart attack. Sebastian, who had been over by the door, was now standing directly behind her, and caught her around the waist. She glared back, trying to ignore the sudden change in her pulse.

His smile was sadistic as he looked down at her. "I knew this would be interesting."

"What are you doing, _Sebby_?"

His crimson eyes flashed dangerously as his arms tightened around her, and pressed her back against a wall. He bent his head low so that his lips were almost touching hers, and his nails scraped lightly against her throat. She wasn't scared, but then why on earth was her heart beating so fast?

"Hm...no smart remarks this time, pet?" He growled, his voice low and dark. "I absolutely _hate_ that nickname, so be careful about using it."

She glared defiantly at him, hardly even noticing that her eye patch had fallen to the floor revealing the Faustian seal.

"My, my. You're blushing."

"I am not!"

Sebastian smirked. "Lying won't do you any good, Nicole."

His lips were now too close, and her heart skipped a beat. The last time he'd been this close to her, it had been when they'd made the contract, and the memory of that drew her gaze to his lips. She'd never admit it out loud, but he was a damn good kisser.

"You're trembling, pet."

"I'm not your pet, yet, _Sebby_."

He let out a low, predatory growl, forced her head up, and kissed her. Again, she was confronted with the fact that his lips were warm, soft, and sinful as he began coaxing her to respond. The hand on her throat moved to cradle her head as he deepened the kiss, and the arm around her waist held her close. For a moment, she was lost in the sensual feel of his lips against hers...and then she gave him a headbutt.

He grumbled. "Nice recovery."

Still blushing, Nikki stormed to the bathroom. "Just see what you can find out about the victims. I need a hot soak."

Sebastian watched as she stalked into the bathroom, smirking. Oh yes, this would be a very interesting arrangement. At least she wasn't as high maintenance as Ciel. With one last look at the bathroom door - and after brushing away the urge to creep in and scare her out of her wits - Sebastian left to do some research.

* * *

Sam and Dean sat outside the hotel - a very expensive one at that - watching for their new "friends". By all appearances, they were normal people, but in their experiences that was never the case. Normal people could be any number of things, and not many of them good.

"Hello, boys."

Both brothers aimed loaded guns at "Ian's" head.

"Oh dear, now that is very unnecessary. I simply wanted to ask you to leave me and _Erin_ to deal with this case."

Dean snorted and shook his head. "Not gonna happen, pal. Why are you two stickin' your noses in this?"

"Oh, I don't think _Miss McNab_ would appreciate me overstepping my bounds." Sebastian smiled down at them. "Good day."

Sam cocked his head slightly, his eyes narrowing as "Ian" ambled off. There was something very very wrong with him, and Sam couldn't figure out what. Yet.


End file.
